The Simpsons is celebrating two milestones this weekend — Sunday’s installment (Fox, 8/7c) is the series’ 600th episode, as well as the 27th “Treehouse of Horror” special — with a little help from (a murderous) Sarah Silverman.

The comedienne lends her voice to Lisa’s childhood imaginary friend Rachel, who returns — from wherever imaginary friends go when their humans stop believing in them — to wipe out all of Lisa’s real friends.

Homer finds himself on the receiving end of Rachel’s fury in TVLine’s exclusive clip from the episode, though he does receive an assist (of sorts) from his own childhood imaginary friend, a literal giant wiener named Sergeant Sausage.

As you’ll see, what transpires is equal parts hilarious and horrifying — not that we’d expect anything less from a Simpsons Halloween special.

Hit PLAY on the clip above to find out if Sergeant Sausage can save the day, then drop a comment with your thoughts below.